DECISION SUPPORT TOOLS FOR OPTIMISING KIWIFRUIT PRODUCTION AND QUALITY

The importance of kiwifruit (Actinidia deliciosa ‘Hayward’) production has increased greatly during the last decade in the Portuguese region of Beira Litoral. However, information on the nutritional status of this crop in this soil/climatic zone is scarce. The objective of this work was to use techniques such as geographic information systems (GIS) and geostatistics to generate information that can be used to optimise physical and financial aspects of kiwifruit production systems. A regional survey was conducted over three years (2002–2004) in 15 geo-referenced orchards of Beira Litoral. Soil analysis and fruit production and quality were determined. In order to understand the variation of kiwifruit quality and production factors, graphical interpretation of these properties was done using GIS, geostatistics and principle component analyses (PCA). Ordinary kriging was the geostatistical technique used for creation of prediction maps, which were then introduced into a GIS and their values reclassified. Maps of biophysical characteristics of the region were then related to the generated GIS/geostatistical maps using PCA. Areas with highest potential production and quality were located. Site specific management methods could improve productivity and quality. Those maps can help the producer to make decisions about harvesting time or localized correction of production factors and to choose the best place for vineyard installation in the region. There was a strong correlation between the map of yield and quality factors. An in-depth analysis of PCA showed which parameters were the most important as production factors for quality and yield; therefore this methodology was important for analysis of relations of different parameters in agricultural studies.